Peterbilt Air Trac Air Bag Suspension Systems - Features and Benefits

An Overview of Peterbilt Air Trac Air Bag Suspension Systems

Peterbilt Motors Company, headquartered in Denton, Texas, is a leading American manufacturer of medium and heavy-duty trucks. Founded in 1939, Peterbilt has long been known for its customization options and innovative features. One such innovation is the proprietary Air Trac air bag suspension system offered on many Peterbilt models.

What is Air Suspension?

Air suspension uses air bags rather than conventional steel springs to absorb road shocks and bumps. The air bags are connected via hoses and valves to an on-board air compressor and tank system. By adjusting the air pressure in the bags, the truck's ride height and suspension stiffness can be raised or lowered as needed for driving conditions or to allow for loading and unloading. Air suspension provides a smoother, more consistent ride compared to leaf spring suspensions.

Key Benefits of the Peterbilt Air Trac System

Peterbilt's Air Trac system provides significant benefits for class 7 and 8 trucks:

• Improved Ride Quality - The air bags isolate the truck cab from road vibrations, providing a smoother, more comfortable ride.
• Better Handling - Air suspension allows for greater adjustability of ride height and stiffness, improving handling and control.
• Reduced Maintenance - Air bags have no moving parts and require less maintenance than conventional steel leaf springs.
• Weight Savings - Air suspension is lighter than steel springs, improving fuel efficiency.
• Driver Comfort - Drivers experience less fatigue on long hauls due to the improved ride.

Air Trac System Components

The Peterbilt Air Trac system includes the following key components:

• Air Bags - The suspension air bags are constructed of tough, flexible reinforced rubber. Peterbilt uses Firestone brand air bags.
• Shock Absorbers - Heavy-duty gas shocks smooth out the compression and rebound motions of the air bags.
• Control Arms - Suspension control arms provide lateral support and help guide the axles.
• Air Lines - High strength nylon lines route air between the bags, compressor, and valves.
• Electronic Control Unit - This computer controls the suspension height sensors and air compressor operation.
• Height Control Valves - Valves regulate the airflow to raise or lower the suspension height.
• Compressor - An on-board air compressor re-pressurizes the system as needed.
• Air Tank - The air tank stores compressed air for the suspension system.

How the Air Trac System Works

The Air Trac system automatically monitors and adjusts the truck's ride height and suspension stiffness while driving. Here is an overview of operation:

1. Height sensors at each wheel continuously measure the suspension height.
2. This data is sent to the electronic control unit (ECU).
3. The ECU tracks ride height and compares it to the target ride height set by the driver.
4. If ride height varies from the target, the ECU activates air control valves to add or release air until the target is achieved.
5. The on-board compressor runs as needed to replenish air in the system.
6. By managing suspension air pressure in this way, a smooth, consistent ride is maintained.

Air Trac Features and Options

Peterbilt offers a wide range of configuration options for Air Trac suspension. Customization and features include:

• Adjustment Modes - "Comfort," "Normal," and "Firm" modes alter the ride stiffness and handling.
• Multiple Axle Configurations - Available for tandem or tridem rear axles.
• Lift Axles - Front lift axles can be added for additional load capacity.
• Ride Height Control - Lowers truck height for loading docks or raises for clearance.
• Automatic Dump Valves - Quickly releases air for faster axle weight adjustments.
• Planetary Axles - Improve traction and load handling on demanding terrain.

Maintenance Tips for Air Trac Air Suspension

To keep your Peterbilt Air Trac system in top working condition follow these maintenance best practices:

• Check Air Pressure - Confirm air pressure is at recommended PSI before operating.
• Inspect Air Lines - Look for damage or leaks. Replace worn air lines.
• Drain Air Tanks - Release moisture from tanks regularly to avoid corrosion.
• Listen for Compressor Cycling - Excessive compressor running can indicate a leak.
• Check Fasteners - Ensure suspension components and air bags are securely mounted.
• Review Service Manual - Follow all maintenance instructions and service intervals.

Air Trac Provides a Smoother Ride

Peterbilt's proprietary Air Trac air bag suspension delivers a smoother, safer ride compared to leaf spring suspensions. The system adjusts automatically to road conditions, while also allowing drivers to customize suspension stiffness. With proper maintenance, Air Trac will provide years of comfortable, reliable service.

FAQs

What are the main benefits of Peterbilt's Air Trac air suspension?

The main benefits are improved ride quality, better handling, reduced maintenance needs, weight savings, and increased driver comfort compared to leaf spring suspensions.

What models can get Air Trac air suspension?

Air Trac is available for Peterbilt class 7 and 8 models including the 567, 568, 579, 587, and 588.

How does the Air Trac system monitor and adjust ride height?

Sensors at each wheel measure current ride height. An electronic control unit compares this to the target ride height set by the driver and activates air valves to reach the target height.

What maintenance is required for Air Trac air suspension?

Check air pressure regularly, inspect air lines for leaks, drain air tanks, listen for excessive compressor cycling, check fasteners are tight, and follow the manufacturer service intervals.

Can I adjust the ride stiffness with Air Trac?

Yes, Air Trac has adjustable modes including Comfort, Normal, and Firm to customize stiffness and handling.